Phineas's Plea And Candice's Kerfuffle
by Logical Swimmer
Summary: Phineas's horniness drives him to ask a favor of Isabella, luckily for him she's been waiting for it. UPDATE: (by request) Two weeks after chapter 1, Candice walks in on Phineas and Isabella in the act. See what happens next! Warning, if it wasn't obvious, lemons! Incest! Candiphinebella! Rated M for obvious reasons.
1. Chapter 1

There was a knock on Phineas's bedroom door. "Hey, Phineas." Isabella poked her head in shyly. "I got your text that you wanted me to come over. So, what'cha doin'?"

He lifted his head from his pillow where he lay resting in his lifeboat-themed bed. "Nothing. Absolutely nothing. And until my broken arms heal, I have no choice but to continue to do nothing."

She took another look at the two casts cradling both his arms from above the elbow down to his fingertips. "I sympathize," she offered, taking a seat at his bedside. "I haven't ever broken a bone, but due to my first aid training, I understand it's quite a bummer."

He snorted. "You got that right. First off, the pain of initially breaking them was excruciating, then the doctors had to reset them back in place, which was ten times worse. Once the pain ebbs down to a dull ache, the worst part is having to sit around for a whole month, waiting for them to heal. No inventing, no fun, nothing. I wouldn't wish this on my worst enemy, if I ever was to have one." He let his head hit the pillow again, frowning dejectedly. "All because I fell off that waterslide Ferb and I built on Tuesday."

"That does sound awful," Isabella said.

"Yeah," Phineas said with a heavy sigh. He carefully sat up, taking care not to put any pressure on his sore arms, using only his stomach muscles, swinging his legs, and shifting his hips so he could sit next to her properly. "It would have been one thing if I had only broken just _one_ of my arms," he continued. "Then I could still use my other hand, at least. With literally no hands, though, everything you take for granted becomes almost impossible. Eating, brushing your teeth, going to the bathroom..." He gestured half-disgusted with his casts. "Ferb is working on an invention right now that will at least help me put my clothes on in the morning, since he's tired of taking turns dressing me with Mom. I even have difficulty texting people."

"Oh my gosh, I'm so sorry, I had no idea!"

"Needless to say, it sucks. And I'm usually the optimistic one."

The Fireside Girl took compassion on him. She put an arm around his shoulders, saying, "Phineas, if you ever need anything, you know I'm right here."

After enjoying the touch for a moment, Phineas said, "It's funny you should ask..."

"What's up?" Isabella looked into his eyes.

He hesitated and blushed. "It's..." He cleared his throat, noticeably uncomfortable. "Isabella," he finally said, "w-we're best friends, right?"

"Yeah?" She said, not sure where he was going.

"And we can talk to each other about, um, anything, right?"

"Of course," she said immediately.

He was shifting and squirming. "You have to swear you won't tell anyone about this. Promise?"

Now she was worried, but also extremely curious. "Okay. I promise."

He gave a heavy sigh. "Alright," he said. "I'm just gonna say it. Isabella, I need your help with something very badly. It's, really embarrassing, and I never thought I would be telling anyone this, but it's driving me crazy. Like, literally, crazy!" He stopped to catch his breath. "Before I broke my arms, I-" He stopped, then tried again. "When I could still use my hands, every day I would... I would-" His face turned red and he looked away. She felt him shudder beside her.

"Why's it so hard?" He asked. "Bleh. I can't say it." He slouched in embarrassment.

"You would what?" She asked. "You built inventions? You played the piano? You diced onions? Drove your truck?"

"Well, yes, but none of those are what I'm talking about," he answered.

"Then what?" She prodded. "Spit it out!"

He sighed audibly, and stood up to walk a pace away from her. "I did bad things," he finally admitted. "I - masturbated - every day."

The room went dead quiet.

He didn't dare to look at his crush's face. He was blushing too hard, and he knew it. Not to mention, although he wouldn't dare say it, she was the person he thought about when he did his daily deed...

As soon as he said that word, Isabella's heart began racing. The boy she had been in love with but who was totally oblivious to her affections for all these years had just caught her completely off guard. It was a good thing he was facing away from her, because she figured her face was probably redder than his hair, she was blushing so much.

Now that it was out, he finally turned around and dropped to his knees. The rest just flowed out like a waterfall. "Please, you can't tell anybody! Not even Ferb knows! I'm sorry to be telling you like this, it's just that I'm sooo horny, all the time, and I can't help it! I just can't focus on doing anything else until I do it! And then both my arms broke, and now I can't do it anymore! Because first off, my casts are too scratchy, so it doesn't work very well, and secondly, I have no grip strength, so I really am incapable. This is what I'm asking you for, Isabella. I haven't gotten off in four days! It's driving me insane! I promise, I'll do anything for you if you help me with this! I'll help you get any Fireside Girls patch you need, or make you any invention, or even be your personal servant, once my arms are healed, of course. Please, Isabella, I'm begging you! And I'm not asking to have sex, or anything like that. I'm just talking, like, a simple hand job. That's all I want. You have no idea how hard it is asking you this, but I'm at my whit's end, my hormones are going completely bonkers, and there is honestly nobody else I can turn to. Oh, Isabella, won't you please?"

The term "like a deer in the headlights" perfectly described Isabella's face right now. Not to mention that her innards were turning to a horny gooey mess. She could feel the heat between her thighs turning up with every single one of the boy's sentences. Now she was probably wet, too.

When she didn't respond immediately, Phineas blushed even harder than before. "Oh, I'm sorry, what am I saying? That's ridiculous." He stood back up and pointed at the door. "Sorry, Isabella. Can you just leave and pretend we never had this conversation?"

When he stood, she couldn't help but look at his zipper. He wasn't lying, it would appear. It looked like he'd been as turned on by admitting to her as she had been. The bulge was obvious.

One thing was certain, though. Isabella knew that she finally had him right where she wanted him. She quickly came up with a plan.

She stood up, pretending to leave, as he asked. Then, with a dramatic flair fit for the theatre, she stopped right at the moment she was twisting the doornob. "Wait," she said, turning to face him. "If I do this, you promise you will do _anything_?"

"Anything." he said. A fleeting hope came to his face.

Inwardly, she was feeling exactly the same. "Okay." She clicked the door locked instead.

If they weren't in casts, Phineas's hands would have been shaking with nervousness as she approached him. She stopped an arm's length away, trying to figure out how to begin, he assumed. He realized, just then, he didn't know what to do, either. After all, his only resume of sexual experience was his alone time. Being with another person, especially the hottest girl in school, who he liked, was so different. Which was scary. And exciting.

"So," he said, "this is more awkward then I thought it would be. You do, um, know how to do it, right? Because now that I think about it, I guess I sort of made that assumption in haste-"

"Shut up," Isabella, said, rolling her eyes. She pushed him towards the bed, and he sat down obediently. Now that you mentioned it, her fingers were shaky too, as she unpopped the button of his blue cargo shorts, unzipped the zipper, and tugged them down by the waistband. She did it all with great concentration, trying not to touch his body yet, any more than possible to manipulate the clothing. To think that she was mere moments away from seeing Phineas naked was almost enough to make her lose all motor function entirely. Being this close to him didn't help either. After all, her face was just inches away from his groin, and she still felt that bulge anyways when she brushed against the zipper!

He shifted from side to side to let his shorts slide past his buttocks and down to his ankles. She pulled his feet through and tossed the shorts behind her for good measure. He leaned back, expecting her to give his boxers the same treatment, but instead she kneeled down between his knees and slid her hands slowly up his thighs. She stopped at about the halfway point between the length of his boxers and his hips, just to watch. Already, he was pretty much fully erect underneath. A small part of him was peeking through the "pee hole" boy's boxers had, and she pinched the sides of the fabric and pulled, widening the gap, so that it slid part of its way through. Isabella was now inches away from Phineas's exposed penis.

"Hm, you're smaller than I expected," she teased.

"I am?" he gulped.

"Yeah, see? Just my one hand is bigger than it." She curled her fingers and thumb around his penis from the tip to where the boxer slit was, covering all his exposed skin. It was very warm.

"There's more underneath my boxers, you're not covering it all," he said in his defense. Man, even just her touch felt amazing! And she wasn't even trying to stimulate him, yet! Then again, after four days of not masturbating, anything felt good.

"Oh, is that so?" She said. "Well, then why don't you lie down properly so that it stands up better? Then we'll see." She let go, and he felt a throb of regret, missing her warmth already. So he quickly did as she said, resting his casted arms back against the headboard of the bed so they were out of the way.

Isabella climbed seductively between his legs, bowing to his statue with her rear end pointing straight up in the air. She slid her fingers into the elastic waistband of his boxers and slowly pulled them down his hips. Knowing that they would stimulate him as they pulled back on him, since he was still sticking through the hole. He raised his legs so she could take them all the way off, moaning when they pulled on his sex organ, then spread them wide again around her.

Now as he lay, he was standing firmly upright. Isabella curled her fingers around his shaft, from the base of his pelvis, this time. His head just poked out above her thumb. "No, you're still only five, maybe five-and-a-half. Nothing special."

"Ah, but it's not the size of the dog in the fight, but the size of the fight in the dog."

Isabella smirked. Then she squeezed. Just a little tightly.

"Ah!" He gasped in pleasure.

She saw the sheen of a dribble of pre-cum leak from the tip. She dabbed her thumb in it for lubrication, and started rubbing small circles in the nub on the underside of the pink flesh. He oohed in satisfaction. She let more of her fingers, then eventually her whole hand, begin sliding up and down in a staccato motion.

To him it seemed that having someone else touching him felt far better than doing it himself. He hypothesized that this was because he couldn't subconsciously predict where the sensation would be coming next, which was somehow highly arousing.

Pumping faster now, the bed was starting to shake just the tiniest bit to the rhythm of her pumping. "That feels amazing!" he said, panting. Isabella also was sure now that her panties were going to be soaked soon, if they weren't already. She was enjoying herself just as much as he was. And to be honest, she didn't care that he was average-sized. She just liked teasing him about it.

His head was leaking faster now. It hadn't even been two minutes, and he was already this close to orgasm? Isabella was hoping to enjoy this for just a little longer, but she also had a surprise in store for him and she didn't want him to ruin it by coming too quickly. "If you think this feels good, just wait until you see this!" She stopped pumping for a few seconds, making sure she had his attention, and also to feel him throb from both loss of stimulation and out of anticipation. As soon as their gazes met, she stuck out her tongue and licked the bulging urethral channel running up underneath his member from the lowest point all the way to his tip, stopping to swab at the juicy orifice.

"Oh my gosh!" Phineas burst out. The shiver that ran down his spine at her action shook the whole bed.

Never severing contact, she brought her lips down the rest of the way and further, licking and sucking his circumsized head while gently rocking his shaft with her hand. He was definitely close now, so she went very slowly and softly, trying to see if she could hold him off a bit longer.

"Go faster," he said, waiting in anticipation to climax. "I'm almost there!"

That just made her stop. "You know," she said thoughtfully, as if to ignore his command, "I think I found my new favorite summer activity. Sucking your cock-sickle!" With a grin, she went down on him all the way, no holds barred, mouthing him all the way as far as her mouth had space. She could almost reach the base of his manliness with her lips, if she could just overcome her gag reflex, she'd be there! She slid her tongue all around as she bobbed back down again and again, lubricating him, making her way closer and closer to completely enveloping him with her mouth. Five, six, seven times, she went deeper and deeper, finally losing count. With one last push, she went all the way, with Phineas now thrusting up into her, and she swallowed him down to his pelvis. Her throat clenched around his sensitive area tightly, and with this final burst of stimulation, he spewed his semen down her throat with a great moan of ecstasy.

She held him in for as long as she could hold her breath, letting him ejaculate his entire load down to where it's never coming back up. After some twenty seconds, he was slowing, his moans quieter and his breathing slower, and his penis softening and relaxing, easing back into her mouth so she could breath again, and give her a taste of the liquid riding on his final few contractions. She finished the job by slurping up what was left like a straw, leaving no trace and no mess on the bed for him to have to clean up or explain to anyone, until he was fully shrunken for recovering.

"That. Was. Incredible." He said.

"Glad to hear my services were satisfactory."

He looked at her through lidded eyes. "If I didn't know any better, I'd say you've done this before."

She shook her head. "Nope. I guess I'm just a natural." Although, she didn't say it, she learned from watching porn and reading fan-fictions. She then slithered upwards until she was laying on him and kissed him, not hesitating to go full tongue as soon as he accepted it. She didn't hold back as she traded her saliva for his, then knotted their tongues in an electric embrace.

When they finally broke apart, she giggled and nuzzled into his cheek. "Now _that_ is what I've been waiting for all these years."

Helooked into her eyes. "What do you mean by that?"

She sighed quietly. "I guess it's my turn to admit some things. I've had a really huge crush on you ever since we were kids. I've always dreamed we would do something like this someday."

"Really?"

"Yep."

"I had no idea." He paused for a moment. "I have had a crush on you too, ever since middle school. Maybe even before, but I don't know if I understood my feelings that well back when we were kids."

"Aww." They kissed again, relishing in their moment together. "I am so happy right now," Isabella said a bit later.

"Me too."

"You know what would make me _really_ happy?"

"What?" Phineas asked.

She grinned widely as their noses touched. "Going back for round two."

"I don't know if I can," he hesitated. "That was a really big one to have to come down from. I might need to rest a little longer."

"Or, you might just need a little extra motivation." She sat up, straddling his hips, and slid the straps of her pink dress over her shoulders and down her arms, then took her white undershirt by the waist and lifted high, pulling it all the way off and leaving only her bra remaining. "I imagine these will do."

"I think you just might be right," he said, his eyes getting big.

Tossing her shirt aside, she gave her bra the same treatment. Putting her breasts on full display for her new boyfriend. From her position, she could tell it was working, she felt something start to press slightly against her behind. She rubbed her breasts and pinched her nipples, giving him his personal show, getting her nipples to stick out, giving herself some of the pleasure. It turned her on just as much to rub her flat, toned stomach, imagining she could feel Phineas' loins climb into her belly via her vagina...

Phineas had a lustful look in his eyes. "Oh, how I wish I could hold those," he informed her breasts, lamenting his useless hands.

"You'll get your chance, but for now, you are only getting the appetizer." She said. She rose to her feet on the bed, still standing over him, letting him see up her skirt, which she unbuckled and kicked off, so that she was standing over him in just her panties. Her crotch was totally soaked now, so that their hot pink color became a darker burgundy at the borders of her genitals. She turned around and knelt again, assuming the 69 position by lowering herself to his face and bending over so her mouth could reach his groin. However, she let her fingers dance over his still hardening phallus, preferring to watch it stand on its own in response to her teasings. It didn't take long, now, as he started to slide his tongue up and down her nook, and her spine shivered in pleasure. Returning the favor, she pulled his penis sideways and licked it all along its side, depositing enough saliva that she could now pump it with practically no friction.

Behind her, Phineas gasped, and he lunged his hips upward into her caressing. She was slightly annoyed that he had removed his tongue from her genitals, which had felt so good, but the girl pushed through it, realizing that she must have been driving him out of his mind if he couldn't even focus enough to do his part for her. By the time her initial deposit of saliva was evaporating, she transitioned seamlessly from hand to mouth, bobbing up and down a few times, then licking his whole length, then going back to sucking on it some more, then lifting her other hand to tickle his scrotum.

He still wasn't getting as hard as he had been the first time, but he was being more noisy this time. His head swiveled back and forth, moaning each time he did so, having completely forgotten he was supposed to be stimulating her. She solved the problem, without ever taking her mouth off of him, by slipping her extra hand down between them and massaging herself over the damp cloth. That helped, but she decided it was time to take the panties off. She let his penis slide out of her mouth with a pop and took a moment to yank them down her legs. Then she moved back exactly how she was, accepted his penis back inside her lips, and _finally_ started stimulating herself by tracing circles on her sweet spot. She hadn't had her most sensitive area, her clitoris, touched until this moment, and holding off for so long had only ramped up its sensitivity! She had no doubt this was the most aroused she had ever been in her life.

For Phineas this was the first time he had seen female genitalia in real life, aka not diagrams in his biology book. He'd never watched porn, he knew he'd get caught by Ferb eventually, that man was just too good with computers. And now he was getting a close up look, watching Isabella deftly use her fingers to pleasure herself. And just above, was her nude, pink fanny, arched beautifully into the air. The two cheeks were spread wide so he could gaze upon her dark, button-shaped butthole, it clenched and softened slightly but noticeably with her pelvic floor muscles as their tension continued to march towards consumation. Between his full view and Isabella's good work on him below, he reached an elevated level of arousal that overpowered his fatigue. He swelled to being fully hard within seconds, and quickly felt another orgasm approaching. At that moment, Isabella's index finger went from her clitoris to her vagina, and slipped inside past her second knuckle. That beautiful sight pushed him over the edge. He imagined his penis entering her, finding it's grand purpose as the instrument of both their pleasure. Wondering what the walls of her pelvic muscles would feel like, tightly enclosing his extension from all sides. What his hardness would feel like to her, pushing for space inside her lower abdomen, spraying his seed into the nether reaches of her belly. With that thought on his mind, he cried out, "I'm gonna climax!"

At the same time, Isabella had removed her fingers from her clitoris because it was too sensitive, opting to push in and out of her entrance. She was getting close to orgasm, too. When Phineas cried, "I'm gonna climax," her excitement reached a fever pitch, anxiously awaiting a second drink from her new personal drinking fountain. It was like drinking milk from a very large, suckable nipple, she thought. From his penis, warm liquid gushed into her mouth, where she swished it around without swallowing, knowing that this stuff in her mouth would make her pregnant had it entered the orifice her finger was pushing in and out of. Said stimulation was paying off also, now she was seconds away from coming herself. Her lips were still pressed on his throbbing penis. She increased her finger speed and swallowed all of his semen at once, moaning at the sensation, loving the feeling that what was once a part of Phineas was now a part of her.

That did it, she came! Wave after wave of euphoric bliss hit her, smashing her brain with an overload of dopamine. She tried counting her contractions, but was so blown away she couldn't even make it past three. Every contraction wracked her body with uncontrollable pleasure. She collapsed over Phineas' body, unable to hold herself up, unable to do anything, until multiple waves had washed over her, finally giving her a chance to catch her breath. The intensity of her climax ebbed away, leaving them both drained physically and emotionally, but very happy all the same.

Isabella pushed herself upright and laid down at his side. They laid together, resting, for a few minutes in silence, until Isabella spoke. "Instead of saying, 'climax', you should say you are cumming, instead. Climax sounds kind of weird in the moment."

"Does coming mean the same thing as orgasming?" he asked.

"Yeah. You didn't know that?" she said.

"I'm told I'm naive." He said.

"It's alright," she said, slipping her arm up his shirt to rest it on his chest. "That's what I like about you. I know you are an innocent guy, which means I can trust you as my boyfriend."

He smiled. "Good."

They snuggled for another minute before Isabella raised her eyes to look up at him. "Unfortunately, I wish I could stay here all day, but I have to get ready for a troop meeting here soon."

"That's okay," he said. "We probably don't want to lay naked here for too long anyway, since you never know in this house when someone is about to barge in without knocking."

With a heavy sigh, Isabella straddled him up, giving him a kiss and one last look at her breasts as she sat up on him. "I've also been thinking about that thing you promised me, that you would do anything I asked."

He raised an eyebrow. "And?"

"Here's what I order you to do. You are going to let me come over and do this again every day."

Phineas smiled. "I'll do it," he said.

"That's not all," she said. "We aren't going to be doing any more of this, 'coming in five minutes or less' stuff like we did today. We are going to need to build your stamina, because when your arms heal, you are going to have a lot of interest to pay back, starting with screwing me for two hours straight every day."

His eyes got bigger, like a kid in a candy store. "Okay! Sounds like a fair deal to me!"

With a nod and one last kiss, Isabella got up to dress herself and leave. She walked home, said hi to her mom, and locked herself in her room to take them back off again and dive into bed, spreading her legs. After all, she had to build up her stamina, too.


	2. Chapter 2

Phineas's tongue was so deep in Isabella's mouth she could have swallowed it when the door slammed open. They broke apart at the sound.

It was Candice.

"Phineas, Mom said she's going to be leavign me in charge... WHAT THE?"

Isabella yanked the covers over their naked, intertwined bodies, but it was too late. The damage had been done.

"Are you two... having sex?" she asked.

Phineas yanked the covers over his head to hide his embarrassment. "Ever heard of knocking?" he yelled.

"Ever heard of locking the door?" she yelled back, hiding the key to the boy's room she had used behind her back.

Isabella was glowing a shade of red that matched the casts on Phineas's still healing broken arms. He poked his head out a peep to watch Candice with angered eyes.

The older sister was still in shock, but started to shake it off. Now she grinned psychotically. "You are _sooo_ busted!" she squeed. "So busted! So busted!" She danced around like a complete idiot. The couple in Phineas's bed momentarily shared a confused look.

"I gotta admit," she said, finally ending her sing and dance routine, "I'm very proud of you, bro. And at the same time, discusted at seeing my younger brother naked. But mostly proud." She came and sat next to the two of them on the bed and patted her brother on the head, which he did not appreciate.

"You do know you are making this extremely awkward and uncomfortable for us, right?" Phineas asked while he his girlfriend tried to sink deeper into the covers at the intrusion.

"Yes. Yes I do. Consider this payback for all the times you and Ferb embarrassed me in front of Jeremy."

"Okay," he and Isabella groaned. "Mission accomplished. Now can you please leave us alone?"

She ignored this, and instead reached out and started stroking Isabella's hair. "And Isabella is just gorgeous! You're a lucky guy, Phin. She should be totally out of your league, because, sorry to be so blunt, but the whole, triangle-headed thing, it's not a good look. Way to go, sport! You remind me of me and Jeremy! Two extremely attractive people being just perfect for each other! Except for, you know, only one of you is extremely attractive in this case."

"Gee, thanks," Phineas responded monotonely, and hating Candice more and more by the minute. "Are you done yet?"

Faster than lightning, Candice ripped the blankets off the bed, exposing the two lovers entirely. Phineas and Isabella instinctively covered themselves with their hands and blushed even more than they were before.

"Whah! Candice, you're taking this too far!" Phineas was trying his best to cover himself, but seeing as he was wearing casts on both arms still, he had to twist into the fetal position and use his legs mostly.

"You're smaller than I thought you would be," she snickered at the sight.

"I'm shrunk up right now because of you, moment killer!" he retorted.

Then she returned her attention to Isabella. "Dang, girl, you've grown into a sexy beast! You know, Phin, I might be a little jealous," she teased.

"You really think I'm pretty?" Isabella asked and still blushing more.

Candice just leaned down and kissed her, to everyone's surprise. "Does that answer your question?" she said.

Isabella looked stunned, and couldn't say a word. Taking the initiative, Candice scooped her face up and kissed her deeper, and after a second's hesitation, Isabella kissed back. Phineas ogled, not sure whether to be upset or aroused. Probably the latter. They continued to kiss, Candice slipping her tongue into Isabella's mouth and using a free hand to massage her boob. When they broke away, Phineas could see a stream of drool connecting from their lips briefly.

"Yummy," Candice said.

"Did that really just happen?" Phineas said.

"Would you rather I go tell Mom that you and Isabella are having sex?" she replied. He looked away. "Yep. I'm joining in." She said, without waiting to start taking off her tank top shirt.

"I don't know," Isabella said, "I've always wondered what it would be like to do it with a girl, but I'm with Phineas now."

"And you're my sister!" Phineas shouted. "That's discusting!"

"That's why threesomes are just for fun," Candice said. "You two can still be together, this doesn't mean I'm not still with Jeremy. It's just-for-fun sex!"

Now that her clothes were off, Phineas stopped complaining. He had never seen Candice naked before. He couldn't help but feel himself growing at the sight, and he didn't feel as ashamed as he thought he should.

She climbed on the bed and straddled Isabella's waist with no further resistance. Phineas watched her grind on his girlfriend and then bend down to start sucking her nipples. He was quickly reaching his full erection, having just at that moment discovered acts of lesbianism really turned him on. Especially when it was two beautiful girls he was watching. Isabella's nipples hardened and her back arched to her touch, with a moan Phineas was now quite familiar with. Suddenly realizing he was missing out, he took command at Isabella's other boob, and now she was having both nipples getting sucked on and licked and played with. She moaned louder, while Candice slurped loudly.

Candice moved over to lay on Isabella's side, giving Phineas room to her other side, and threw a leg over Isabella's thigh. That way she could rock gently back and forth, grinding on Isabella's leg, and she bent her knee up to give Candice more skin to work with. She could feel the wetness leaking out of Candice as it smeared up and down her thigh, thinking that it could drip down and mix with her own moisture she was producing down there. Phineas bit her just the way he knew she liked it, and she let out an involuntary yelp, losing her train of thought in pleasure. Meanwhile Candice's hands were inching downward to Isabella's pelvic region, but not without feeling all around her torso first, front and back, from her smooth stomach around her showing ribs and to her muscular back and down her spine. That felt amazing. Phineas's hands couldn't glide like that, not while they were still on the mend.

Without warning, Candice pressed her hip into Isabella's mound, then drove upwards, grinding her long leg straight into her clitoris. The shocking pleasure jolted her almost to sit upright, smothering Phineas's face with her breasts, who couldn't move so well in his casts, or prop himself up. Isabella used her momentum to grab Candice and roll on top of her, intending to give her the same treatment and make the newcomer come first.

Now Candice was pinned under Isabella, who dove in to start sucking on Candice's nipples. With her fanny pointing high in the air, it wasn't long before she felt Phineas pull her cheeks apart and dart his tongue into her rectum. Doing her best to ignore it, she focused on Candice, using every trick she knew to keep her guessing where her mouth was going next... Her left boob, her neck, under her chin, her ear, her other boob, the middle space between them, her shoulder... And always trying to keep her hands just as active too, rubbing and feeling all over Candice's body. Phineas's tongue went south, distracting her for a moment, but she powered through and kissed Candice deeply. They pretzelled their tongues and Candice sneakily spanked Isabella's behind before groping down all along her thighs.

At that moment, Phineas finally crawled from the girls's side to between Candice's legs, which spread to make room for him. He laid down to bring his face close to Candice's flower and get his first close-up view of his sister. He could see the similarities and differences between Candice's vulva and Isabella's. While Isabella's lips were browner, Candice's were pinker and stuck up more. Her clitoris was a brighter shade of red. He hesitated briefly at going down on his sister, but quickly got over it and put his lips to her skin. Swishing his tongue in ovals and then sucking the soft mound at the top, then dabbing with his tongue at her entrance to test it. It was smooth and liquidy, so he slipped the tip of his tongue inside. Candice's hips bucked upward in response, inviting him to go deeper. He chose to switch over to Isabella's vulva instead, licking it all with one, long swipe of his tongue. To keep the two girls guessing, he started playing Whack-A-Mole on the two vaginas with his tongue.

The smacking sounds of their kissing stopped when Candice pulled up, trying to slide Isabella up so she could attack her nipples some more. Isabella pulled her dangling hair out of the way as Candice chose a side and sucked. Isabella could rub just the front edge of her pelvis on Candice's stomach, yet it gave her more tinglies than she expected it to. Meanwhile the sensation of Candice's sucking on her breasts was even more intoxicating. She felt her pleasure beginning to spike and realized she was leaking more than a faulty fuel converter - something she only knew from helping with Phineas and Ferb's projects. In fact, her fluids were smearing all over Candice's stomach. Phineas's sister seemed to notice at the same time. She stopped applying her mouth to her breasts and sat up a little, making Isabella move to get off of her.

Candice sat up all the way and said, "hold on, I just thought of something." She walked to the door still stark naked, checked both boys to see that the hallway was clear, and ran to her room next door. The open door was enough to make the two remaining lovers nervous, until seconds later Candice came back with something in her hands. Isabella figured out what it was immediately, but Phineas had never seen one before. He watched with curiosity as Candice buckled it to it to her hips, and then his inventor's mind realized what the black lump of plastic was for. Candice was wearing some sort of artificial penis.

Isabella's eyes got wide. What was Candice doing with a strap-on dildo?

"I hope you're ready for this, Isabella," Candice said, using one hand to grip the shaft to steady it. She walked up to the bed and started to push Isabella onto her back.

"I haven't had anything bigger than my finger put in before," Isabella said. Timidly she spread her legs. "So, go easy on me."

"Isabella," Candice said gently, climbing to her knees and aligning the dildo, "you should know me better than that by now." She softly pressed the tip against Isabella's opening, Phineas watching carefully, got her grip on Isabella's hips, then thrust it all the way in in one great shove.

"GAHHHH!" Isabella screamed and her hands flew down to between her thighs, but Candice wouldn't budge.

"There there, that wasn't so bad, was it?" Candice said calmly, a slight twinkle in her eye.

"I said to take it easy on me!" Isabella gasped.

"Isabella, it's like pulling off a band-aid. You have to just get it over with. Relax." She reached around to pull Isabella up by her buttocks, making sure she had achieved full insertion. She waited while the poor girl got used to it. Isabella's gasps of pain slowly went away, and Candice started to slide out and in the slightest bit, actually being gentle this time. "Relax." Isabella went from grimacing to relaxing, then finally removed her hands. Candice took over, rhythmically sliding in and out, and soon Isabella was starting to enjoy it. Fortunately, she was already so wet and loose, she was quickly adapting to this new change.

Candice looked at her brother. "Phineas, thanks for letting me take your girlfriend's virginity. I am honestly surprised you two hadn't already done this!"

He held up his casts. "I blame these things. We were going to do it after they healed."

Isabella turned her head toward Phineas, and used her finger to say, "come hither." He scuttled closer. "I just need something to help with the pain," she said, grabbing his phallus and squeezing hard.

"GAHHHH!" Phineas yelled.

Candice and Isabella laughed. "Don't be a baby," Candace said.

"That wasn't fair," he said back.

"Here. Let me kiss it better," Isabella said, pulling him by the hilt, and he had no choice but to bring himself to her lips. She took him in, stroking his length while she sucked his circumcised head. Phineas moaned. Candice began thrusting more energetically, and Isabella moaned. The familiar sensation of his pre-cum was filling her mouth. He was trying to lean in so she would go deeper, and she happily obliged.

Double penetration of his girlfriend was the hottest thing Phineas had ever seen. He couldn't make up his mind what to watch. Whether to keep an eye on the dildo, which Candice was pumping in and out of Isabella with gusto, or Isabella's breasts, which bobbed up and down with every one of Candice's thrusts, or Candice's breasts, which weren't as developed as Isabella's, but were slenderer and no less titillating to observe, or Isabella's face, when she looked at him with those big, hungry eyes and swallowed his manliness again. It was sensory overload, and even with Isabella's attempts of late to increase his stamina, he knew his willpower was draining fast. He held and held on to keep from blowing his top, and just when he thought he was about to slip and fall in ecstatic release, Candice thrusted Isabella with her biggest one yet, and she lost her motor control momentarily.

"Yeah, I think she's getting close," Candice said. "How're you holding out, Phineas? Your girlfriend is getting really wet, and I know just the way to finish her off." With the dildo still fully inserted, Candice bent over, slipped her arms behind Isabella's back, and lifted her into the air. "I take front, you take back!" she told her brother.

Isabella, who couldn't move now that she was being held by Candice said, "wow Candice, you're really strong!"

"Yeah, I have to drag Mom around all the time trying to bust these guys, it's given me a _lot_ of upper body strength!" She looked over Isabella at Phineas. "You coming?" she said. "No pun intended."

"Yeah," Phineas said, getting onto his knees too. "I mean, yeah, just give me a second."

He was practically dripping with Cowper's fluid, or pre-cum (sometimes he worried that he knew too much anatomy to enjoy having sex, but what can a scientist do?) so he smeared it over Isabella's anus (or musculus sphincter ani externus,) like a paintbrush to a canvas. Then he carefully slipped in, unable to use his hands much, so he let the natural lubrication do the work. Isabella sharply inhaled as he slid past her sphincter up her rectum. Candice repositioned her arms so to be under Isabella's knees, holding her legs up and her gluteus wide-open. Phineas pushed all the way in, and Isabella's shudder shook all three of them.

Candice did the work, lifting Isabella up and then sliding her back down, so that she was now bobbing up and down on both of their poles. She seemed to know just how much to lift before stopping without either of them falling out, so that the motion was smooth and uninterrupted. Isabella gasped each time she went up, but each time she came back down, getting pegged in both her holes, she let out a muffled whimper. Phineas couldn't imagine what that must have felt like. He made a mental note to make an invention someday where he could swap bodies with a girl, for he was suddenly very curious what having a phallus penetrating between your thighs, up your pelvis, and into your lower abdomen felt like. Especially what that felt like in combination with anal penetration, he imagined the thin inner walls of her pelvic floor muscles being the only thing separating his penis from Candice's dildo, sliding together inside her in unison. The combination must have been amazing, he concluded. His scientific analysis was confirmed when Isabella's back arched, her grip on Candice's shoulders tightened, and her eyes rolled back into her head. Her face was a twisted smile of pure ecstasy.

All that science caused him to remember he too was on the verge of chemical-ing her romance. Phineas began to thrust upward to achieve maximum penetration, and Candice did the same. With a scream, Isabella was hit by a truck-sized orgasm, her body wracking with contraction after contraction. Phineas felt the squeezes of her sphincter push him over the edge, and he exploded into her bowels with a satisfied groan. Candice smirked as she watched the blissful looks engulfing their faces, waiting for them to come down from their highs before lifting Isabella out of her double-pronged cradle and laying her back on the bed.

Isabella and Phineas "ah'ed" simultaneously while Candice stood from off the bed victoriously. "I just gave my brother's girlfriend the best orgasm of her life," she hummed. _"Busted."_

Suddenly Isabella's hand shot up, grabbing Candice by the wrist and dragging her back to the bed. "And where do you think _you're_ going?" she said.

"Hey, where'd you get all that strength from after coming so recently?" Candice said, before she was thrown face-down on the bed. Isabella was already unlatching the strap-on. "Now it's _my_ turn to give my boyfriend's sister the best orgasm of her life!" She said, tightening the belt around her own waist and positioning the dildo, so that it now aimed at Candice.

"Busted," Candice whimpered. Isabella pulled the girl's pink fanny up in the air, then rammed the dildo into Candice's back entrance.

Candice had to bite the sheets. "I'm sorry," Isabella said, "was I supposed to be gentle?" She then proceeded to pound her so hard Phineas thought the slapping would be heard all the way downstairs. Candice grunted in pleasure with every plunge. The very sight instantly made Phineas harden up again, especially when Isabella reached around to play with Candice's boobs while she worked. She seemed to notice, and after she decided she had given Candice good enough payback, she flipped over, pulling Candice with her and with the dildo still in her, so that Candice was then laying on top of Isabella, with the strap-on buried deep inside her rectum. Isabella spread Candice's legs for her, pointing the flower of her womanhood direction at Phineas. "There's still room for one more," she said. Phineas's eyes went wide.

"I don't know, Isabella, do you really think I should do my own sister?"

"Let's ask. Candice, do you want Phineas to screw you?"

Candice mumbled incoherently and nodded weakly.

"Yes, yes she does," Isabella said for her.

After just the slightest hesitation, he moved over and got between Candice's legs. His sister's vagina was beautiful, it's sight was making him horny again. He put forward his casted hands and did his best to spread her lips with his fingers, letting him locate the hole to her entrance. He pressed the tip of his penis against it, feeling the pressure his sister put on his tip, took a breath, and pushed. He sunk in to Candice's crotch, getting half-way in with almost no effort. He guided his member deeper in until he was entirely enveloped by his sister. She was raging hot to his touch. Isabella was already going back to pinching her nipples, and Candice squirmed, bringing Phineas's pubic bone all the way to a stop against Candice's mound. Phineas had just lost his virginity with his sister.

That thought didn't bother him now, as he pulled halfway out before sliding in again, building a rhythm. Isabella felt the rhythm and started thrusting again in the back, giving Candice stimulation in both orifices. Candice couldn't move anymore, she was too overcome with pleasure. One of Isabella's hands slid it's way down her flat stomach and between her thighs, and she danced her fingers over her clitoris, which made Candice buck her hips in ecstasy. On top of that, she bit into Candice's neck, which left the older girl all but drooling uncontrollably. Her unfocused eyes rolled back into her head, her world became lust and gratification. All her pleasure sensors were being stimulated at the same time, scrambling her brain.

Phineas went in the same time Isabella went out. Isabella went out the same time Phineas went in.

The nonstop bombardment of Candice's orifices was too much. Her mind blew, and then, so did her body. She couldn't stop herself from crying out as she went over the edge.

"FUUUUU-"

Her brother hit his high at the same time, and with his last thrust, he threw his head back and groaned, spewing his seed into her. She felt the hot liquid pulsing threw her innards.

Isabella shoved every inch of dildo into her other hole, gripping her by the sex handles on her hips to hold her closer and push in farther. She had nothing else stimulating her, so she didn't join in on the orgasmic assault, and so she was just okay with making sure Candice went way past cloud nine, in fact, she was really hoping it went over 9000!

And it probably was. Between having both holes plugged and the feeling of Phineas's semen gushing into her stomach, Candice came harder than she ever had in her life. Candice's entire body was jolted like she was being electrocuted. If Isabella had been hit with a truck-sized orgasm, Candice's was planet-sized. Every contraction shot through her body and shook the entire bed. Her vagina was squeezing Phineas's manhood so hard he thought it was going to pop off, and that alone made him come harder, hitting another orgasm and spraying another load of sperm higher insider her than the last. Tickling her cervix.

She was still coming! The contractions wouldn't seem to stop!

Isabella, who was still under her, felt every clench of her sphincter against the dildo, and smirked as the girl kept coming. Finally, the contractions started to slow and dissipate. Candice's body flopped weakly back onto her, and Isabella breathed in the scent of her hair while she rubbed her smooth, flat stomach, feeling her catch her breath.

The three were too tired to do much after that. Phineas pulled himself out of his sister once he was shrunken back to normal size, but he just fell to the bed to lay beside them. Isabella left the dildo inside Candice for as long as she continued to lay on her, and seeing as she didn't seem to be able to move right now, that was gonna be a while.

"I think she passed out," Phineas whispered.

"That'll teach her to barge in on us while having sex."

"Yeah," Phineas agreed. "Do you think she'll ever do it again?"

"I'd bet my life on it."


End file.
